Many studies report that comorbid borderline personality pathology is associated with poorer outcomes in the treatment of Axis I disorders. Given the high rates of comorbidity between borderline personality pathology and posttraumatic stress disorder (PTSD), it is essential to determine whether borderline symptomatology affects PTSD treatment outcome. This study examined the effects of borderline personality characteristics (BPC) on 131 female rape victims receiving cognitive-behavioral treatment for PTSD. Higher BPC scores were associated with greater pretreatment PTSD severity; however, individuals with higher levels of BPC were just as likely to complete treatment and also as likely to show significant treatment response on several outcome measures. There were no significant interactions between type of treatment and BPC on the outcome variables. Findings suggest that women with borderline pathology may be able to benefit significantly from cognitive-behavioral treatment for PTSD.